Hydraulic accumulator



Sept. 4, 1923.

J. GRAHAM HYDRAULIC ACCUMULATOR Filed May 15 1916 Patented Sept. 4, 1923.

IINITEE STATES FATE @FFIQBQ JESSE GRAHAM, OF LEEDS, ENGLAND, ASSIGNOR TO BRADFORD DYERS ASSOCIATION LIMITED, OF BRADFORD, ENGLAND.

HYDRAULIC ACCUIVIULATOR.

Application filed May 15, 1916. Serial N0. 97,620.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L., 1313.)

T 0 all whom it may concern:

Be it known that I, Jnssn GRAHAM, of Cragwood House, I-Iorsforth, Leeds, in the county of York, England, have invented a certain new and useful Improvement in Hydraulic Accumulators (for which I have filed an application in England Sept. 15, 191 l o.1-9,T79), of which the following de scription, by reference to the accompanying drawing, is a specification.

In the use of hydraulic accumulators for many and varied purposes, for example in connection with accumulators for calendering or pressing fabrics and for performing other functions, it is often desirable that the pressure transmitted from said accumulators to the goods being treated should be reduced or varied so that for certain classes of goods or to perform certain treatments the pressure may be considerable, while for others it may be lessened to meet the circumstances or requirements of the particular work that has to be carried out. To attain this object I have already designed apparatus for which I have obtained Letters Patent of the United States of America No. 1,259,393, said apparatus being for use in connection with hydraulic accumulators which exert given and fixed pressures, by which apparatus I can attain said object without altering the pressure of said accumulators. In the present instance, as in the application referred to, I make use of a differential piston. in a cylinder, one end of which is connected to the source of pressure and the other to the apparatus to which pressure is to be applied, and this I use in conjunction with a valve or by-pass intervening between said accumulators and the apparatus to which they have to apply pressure controlled by the piston itself in such manner that said valve is moved or operated as and whenever the piston moves. In this arrangement variability is secured by varying the effective surfaces of the high pressure side of the differential piston. In addition to the foregoing I make use of single acting pistons. that is to say, pistons that are moved in one direction only by the pressure water, and this I arrange so that one piston will move in one direction under the pressure of the water while another piston. will move in the opposite direction under the actions of said pressure water.

In order that my said invention may be more readily understood, I have hereunto appended a sheet of drawings which illustrate in elevation (partly in section) devices which I employ The central cylinder 2, which may be styled the main cylinder has its piston 5 extending downwardly to a cross head 50 while its pressure surface is at its upper end at 5". .To this piston is secured a rod 5 which merely acts as means for lessening or varying the pressure area 5 of said piston 5 and 1s detachable from sald piston 5 so that it may be replaced by a rod of different dimensions for the purpose of varying the eifective pressure area thereof.

The pressure fluid is supplied to pipe 4 which is open to the pressure of an accumulator (not shown), said pipe having a branch leading to the cylinder 2. Said cylinder is constantly under the influence of pressure fluid when in action and when the fluid is admitted to the cylinder it travels upwardly through the space between the piston and the wall of the cylinder until it reaches the top of the latter and reacts against the upper end of the piston so as to force it downwardly. The pipe I also communicates by means of a branch 4 with the apparatus to which pressure is to be applied such, for instance, the rams of a calendar- (not shown). The branch 4? communicates withcylinders 20 and 20* by means of branches at, which are also in communication with the pipe 45. Working in cylinders 20 and 20 are supplemental pistons so positioned that pressure introduced into said cylinders will act to move the pistons in a of pipe 4. As the cross-head 50 moves downwardly under the force of the fixed pressure, the valve 7 is opened, thereby ad mitting the pressure fluid to the cylinders 20 and 20 through branches i. The combined areas of the pistons 10 and w is greater than the area of piston 5. Therefore just as soon as pressure enters cylinder 20 and 20 the lever 7 is moved upwardly and operates valve 7 to prevent the full power of the pres sure fluid, entering cylinders 20 and 20, thus imprisoning said fluid between pistons 10 and w and the apparatus to which pressure is to be applied. The smaller end of piston 5 is now under the influence of fluid at accumulator pressure, and this is sufiicient to overcome the pressure upon pistons 10 and 'w, thereby transmitting pressure through said pistons to the apparatus to which the pressure is to be applied. Thus the pressure is reduced in the proportion that the lesser area of piston 5 has to the greater combined areas of pistons w and w.

Although I have herein shown three cylinders it may be possible to arrange the separate pistons of only two cylinders to attain the desired result, in which case one cylinder would have its piston to move in one direction while the other would have its piston to move in the opposite direction. Or again, more than this number of pistons may be used in combination with each other, by having certain of them to move in one direction under pressure water, while others of said pistons were caused to move in the opposite direction under the same pressure water.

Such being the nature and object of my invention, I declare that what I claim is 1. A control device for hydraulic accu mulators comprising a main piston, supplemental pistons mouuted to act in opposition to the main piston, the effective pressure area of the main piston being less than the combined effective pressure areas of the sup plemental pistons, means connecting said pistons, means whereby the effective pressure area of the main piston may be changed, cylinders for said pistons, branch pipes'leading from a common source to the respective cylinders, means actuated by movements of the pistons for varying the active pressure the last mentioned branch pipe.

2. A control device for hydraulic accumulators comprising a main piston, supplemental pistons mounted to act in opposition to the main piston, the effective pressure area of the main piston being less than the combined effective pressure areas of the supplemental pistons, cross-heads to which the respective pistons are connected, means connecting said cross-heads, means whereby the effective pressure area of the main piston may be changed, cylinders for said, pistons, branch pipes leading from a common source to the respective cylinders, means operatively connected to one of the cross-heads and actuated by movement thereof for varying the active pressure of fluid passing through the branch pipe leading to the cylinders of said supplemental pistons, and a delivery pipe connected with the last mentioned branch pipe.

3. A. control device for hydraulic accumulators comprising a main piston, a plurality of supplemental pistons mounted to act in opposition to the main piston, the effective pressure area of the main piston being less than the combined effective pres sure areas of the supplemental pistons, said pistons being separate from each other and arranged in parallel relation, cylinders for said pistons, means whereby the effective pressure area of the main piston may be changed, branch pipes leading from a common source to the respective cylinders, means controlled by movements of the pistons for varying the active pressure of fluid passing through the branch pipe leading to the cylinders of said supplemental pistons, and a delivery pipe connected with the last mentioned branch pipe.

4. A. control device for hydraulic accumulators comprising a main piston, a rod detachably connected thereto whereby a rod of different diameter may be substituted, supplemental pistons mounted to act in onposi tion to the main piston, the effective pressure area of the main piston being less than the combined effective pressure areas of the supplemental pistons, means connecting said rod with said supplemental pistons, cylinders for said pistons, branch pipes leading. from a common source to the respective cylinders, means actuated by movement of the pistons for varying the active pressure of fluid passing through the branch by leading to the cylinders of said supplemental pistons, and a delivery pipe connected with the last mentioned branch pipe.

JESSE GRAHAM. 

